ecto-

a combining form meaning “outer,” “outside,” “external,” used in the formation of compound words:

ectoderm.

Also, especially before a vowel, ect-.

Origin

combining form of Greek ektós outside

British Dictionary definitions for ecto-

ecto-

combining form

indicating outer, outside, external: ectoplasm

Word Origin

from Greek ektos outside, from ek, ex out

Word Origin and History for ecto-

word-forming element generally meaning "outside, external," before vowels ect-, comb. form of Greek ektos "outside" (adv.), used to form scientific compounds in Greek; related to Greek ek, ex "out," from PIE *eghs- (see ex-).

ecto- in Medicine

ecto- or ect-
pref.
Outer; external: ectoparasite.